What is the greenest way to use cat litter or is there an alternative I can use? I have three cats and they go through quite a bit of litter per week. I would rather use something that is environmentally friendly.

I would say clay litter but it's not very effective. Or maybe newspaper. It would dissolve a year or two after use when you send it to the landfill. I use newspaper as a weed block when I plant my garden beds.